Thetford C250 won't flush

Discussion in 'Motorhome Chat' started by TheDentons, Oct 6, 2014.

  1. TheDentons

    TheDentons Funster

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    Last week our thetford C250 toilet stopped flushing
    I've put a multimeter on it and have 12v at the switch. Trying to decifer if it's the switch or there's another small circuit board that tells you when the cassette is full.
    Does this disable the flush when tank is full?
    So I can try an isolate the problem.
    Is it the switch or tank censor

    Cheers
     
  2. Jaws

    Jaws Funster Life Member

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    No mate.. the cassette full LED is nowt more than that... it is switched by a float arm with a magnet on it inside the cassette..
    It can really only be the switch or the solenoid ..
     
  3. icantremember

    icantremember Funster

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    It is probably the circuit board behind the press switch has been pushed out of its mounting clips ..... simple to fix by pulling off the switch facia and pressing the board back into the clips.
    Good luck and hope you will soon be flushed with success.
     
  4. TheDentons

    TheDentons Funster

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    Ordered new push switch and reed switch fitted both still nothing the reed switch looks different and the full light is permanently on have 12v to the button but doesn't flush when pressed
     
  5. dabhand

    dabhand Funster Life Member

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    Each time you scratch your ear, pray that it's wax:)
     
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  6. Gizmouk

    Gizmouk Funster

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    Check voltage to the pump when flush button is pressed.
    Or
    Apply a known good 12v source straight to the flush pump terminals.
     
  7. jockaneezer

    jockaneezer Funster

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    Maybe your pump has siezed or stuck ? Can you get at it to give it a gentle tap or at it's terminals to try connecting it direct to 12 volts ?
     
  8. TheDentons

    TheDentons Funster

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    Taken pump out runs fine independently I'm baffled
     
  9. Gizmouk

    Gizmouk Funster

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  10. Gizmouk

    Gizmouk Funster

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    If it's the same housing / type that was used on our old Thetford 402(?), it wasn't easy to see.
    A 3A small blade fuse if memory serves me correct
     
  11. TheDentons

    TheDentons Funster

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    Fuse is fine I have power to the switch, the only thing that I can think of is that it's the wrong reed switch stopping the toilet flush
    An earlier post says the reed switch doesn't effect the flush
    Does anybody know this for certain
    Cheers
     
  12. Jaws

    Jaws Funster Life Member

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    Not according to the installation information it doesn't, but it is possible to modify anything I suppose.. Not sure a reed switch ( unless a big one ! ) would have enough contact area to handle the switching current of a pump or solenoid.

    It does depend if the reed switch is N O or N C ( Normally Open or Normally Closed ) but...

    Simple checks
    If it needs to be open then just disconnect one of the feed wires to it and try the flush ( This seems very unlikely though )
    Just use a clip lead across the reed shorting it out and see if the flush works.
     
  13. jockaneezer

    jockaneezer Funster

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    How old is the toilet ? The reason I ask is in our old Adria caravan a few years back, the toilet stopped flushing and after a lot of searching, I found that the copper wires in the supply cable to the toilet had gone black, a common problem on DC supplied appliances. Anyhoo, I could get 12 volts on my digital multimeter at the bog but not enough current down the wire to run the toilet. Had to run a new supply cable to sort it out :(
     
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